The anniversary clock generally comprises a base upon which a case having at least one transparent surface, is mounted, the clockwork being received in and protected by the case, generally having a torsion pendulum and being provided with a clock face which is juxtaposed with the transparent wall of the case.
Such clock cases have been provided in a variety of forms. In one form the case has a framework with glass panels, the framework being a comparatively massive structure which, while offering some aesthetic features which may be desirable in some cases, may be considered disadvantageous in others. An alternate construction of a clock case for an anniversary clock is a domed glass structure through which the clock within the case can be viewed at any angle. Such a clock case may have a cylindrical wall which merges into the dome. All-transparent clock cases of the latter type are frequently more aesthetic and desirable because they allow the interior form of the interior clockwork to contribute more fully to the aesthetic appearance of the clock as a whole.
However, difficulties have been encountered when efforts to apply a decor to the glass cases of the latter type is undertaken.
These difficulties were most pronounced when the decor was to be applied in the form of decalcomania or decorative foils which had a certain degree of stiffness and were compelled to adhere to the curved surfaces of the case. However, the difficulties were also pronounced when screen printing or other decorative techniques were applied for decorative purposes on the dome or curved surfaces.
Another disadvantage of the domed cylindrical cases was the spatial requirements of the clock since the domed cylindrical case precluded a relatively flat configuration of limited depth.
While the latter problem does not characterize the prismatic shapes obtained when the casing was provided with a frame receiving glass panels, in general such framed structures were not only relatively expensive and time consuming to fabricate, but the casing, because of the relatively massive frame structure, contributed significantly to the weight of the clock.
Furthermore, the metal or other parts of the frame work and the supports for the glass panels in such cases require fabrication by copying milling machines and other expensive tools, decoration apart from the glass panels, which involves still additional expense and, in general, unduly complicates the fabrication process.